Verify Plaid webhook authenticity using the JWT-based Plaid-Verification header and JWK key rotation, rejecting stale or tampered payloads
domain: plaid.com · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
In-depth guide
Plaid webhook verification — the full failure-mode walkthrough related to plaid.com, checked against official docs, with linked verified routes.
Steps
Extract the JWT from the Plaid-Verification HTTP header and decode its header (without verifying the signature yet) to read the alg and kid fields
Reject the webhook if alg is not ES256
Call /webhook_verification_key/get with the extracted kid to retrieve the JWK public key, caching it in memory keyed by kid
Verify the JWT signature using the JWK and check that the iat claim is no more than 5 minutes old to prevent replay
Compute the SHA-256 hash of the raw webhook body and compare it in constant time against the JWT's request_body_sha256 claim before trusting the payload
Known gotchas
request_body_sha256 is sensitive to whitespace in the stored body (tab-spacing of 2 vs 4 produces different hashes), so hash the exact bytes received rather than a re-serialized copy
Key rotation means a cached JWK for an old kid can go stale; if verification fails, re-fetch the key by kid rather than assuming a bad request, but still reject if verification ultimately fails
Plaid documents webhook verification as optional, so skipping it is technically valid but leaves the endpoint open to spoofed webhook payloads
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